This invention relates to a CATV converter, and more particularly to a converter wherein an input TV signal is converted into a frequency of a specific channel.
Ordinarily, in a CATV converter of conventional construction, a number of TV signals divided into, for instance, 30 channels are converted by a frequency converting circuit into a frequency of a specific channel (of for instance, Channel 2). Accordingly, by connecting an ordinary TV receiver set for Channel 2 with the converter, any one channel can be selected from the number of channels by manipulating the channel selecting buttons on the converter.
However, in the case in which channel selection by the button on the converter is for the same channel (e.g. 2) as the TV receiver setting, the input and output frequencies of the converter are made substantially equal (to the frequency of Channel 2), thus creating a beat frequency (a so-called channel beat) and deteriorating the image quality. Although no beat will be created when the frequencies of the input and output are absolutely equal, a slight difference always exists therebetween particularly when one part of the input signal leaks to the output side or one part of the output signal leaks to the input side through peripheral circuits, and the beat creates a stripe-shaped irregularity on the picture tube.
An object of the present invention is to provide a CATV converter wherein no beat is caused, even when the selected channel coincides with the specific channel.